The following is an example of method of manufacturing a liquid crystal display device. Switching elements (e.g., TFT) and pixel electrodes are arranged on one of glass substrates provided in a pair, and counter electrodes are arranged on the other glass substrate. Those glass substrates are then bonded with spacers between them. Liquid crystal is disposed between the glass substrates so as to form a liquid crystal layer. Polarizing plates are attached to respective surfaces of the glass substrates, and then a liquid crystal panel is produced. A lighting device that has a plurality of cold cathode tubes as light source is mounted to the liquid crystal panel.
In such a production process of liquid crystal display device, a defect detection using various inspections may be performed at a predetermined point. In an inspection after a liquid crystal layer is formed, for example, a pair of test polarizing plates is arranged so as to sandwich both glass substrates. A test backlight is turned on, and a switching element is driven to detect display defects.
In such an inspection process, if a foreign substance is present in the liquid crystal layer, light is irregularly reflected by it, which may create bright spots on black display. These spots would be detected as luminance point defects, and greatly degrade the display quality and yield in production.
A method of compensating for a luminance point defect as shown in Patent Document 1 is known, for example. In Patent Document 1, a processed concave portion is formed near a surface of a transparent substrate that is located in a travel path of light that illuminates a pixel element in which a luminance point defect is present and on an incidence side. Sides and bottom of the processed concave portion are finished by surface-roughening so as to form a light scattering region.    Patent Document 1: JP-A-04-301617